1. Field of the Invention
The present invention relates to a method for performing a reaction, such as the synthesis of concentrated cDNA, in the wells of a microplate while minimizing the volume of the solution of reagents required to perform the reaction.
2. Description of the Related Art
Plastic microplates have become an indispensable tool in biological and chemical research and development. These microplates feature a plurality of wells (in the standard format, there are 96 wells per microplate) in which separate reactions can take place. They are particularly useful in performing processes requiring the immobilization of substances on a surface (the walls of each well), followed by reaction of the immobilized substances with a reagent or reagents, and rapid assessment of the results in the various wells of the microplate. Depending on the composition of the microplate, there are various substances that can be immobilized to the microplate wells. These include, for example, long oligonucleotides and cDNAs, amino modified oligonucleotides, amino modified cDNAs, proteins, carbohydrates, cells, lysates, tissues, and chemical subunits such as monomers. Microplates to which such substances have been immobilized may be used, for example, in gene expression microarrays, SNP detection microarrays, and protein microarrays, among other applications.
The wells of these microplates have various shapes: some have flat bottoms, while others have rounded bottoms or v-shaped bottoms, leading to a conical well. Typical working volumes of the wells are 75-250 μl. In order to conduct reactions in these wells, it is presently necessary to transfer an amount of reagents to the wells sufficient to cover the surfaces of the wells to which the substances are immobilized. However, these reagents are often quite expensive: for example, polymerase chain reaction enzymes such as reverse transcriptase and RNAsin can cost as much as $7 per reaction in the amounts conventionally required. It would accordingly be desirable to economize on the use of such reagents in conducting the biological reactions.
Furthermore, the development of a standard amount of a reaction product while using a smaller volume of reagents can result in a more concentrated solution of reaction product. This can be important when the resulting solution is assayed for the presence of the reaction product (via fluorescence assay or the like), as the higher concentration of reaction product will lead to a stronger signal.